海洋石油开发工业污染物产生系数和排放系数研究

污染物产生系数和排放系数是工程环境影响评价的重要指标,但对于海洋石油开发工程环境影响评价来说,迄今尚无具权威性的系数可资使用。在我国近海石油开发工程污染源系统调查的基础上,对海洋石油开发行业污染物产生系数和排放系数的定义、计算方法、应用范围及应用方式进行了探讨,研究结果可为海洋石油开发工程项目环境影响评价及环境保护管理,以及行业或企业有关标准的制定提供参考。     

Quasi-static and dynamic crushing behaviors of aluminum and steel tubes with a cutout

Tubular members are commonly used as an energy absorber in engineering structures and many such members have a cutout. In this study, the crushing behaviors of tubes with a cutout are characterized and the effects of cutout on the energy absorption capabilities of these tubes are quantified. Systematic parametric studies were carried out to study the effect of material properties, including yield and ultimate strength of material, strain rate effect, location of cutout, tube length and impact speed on the crushing behaviors and energy absorption capacity of aluminum and steel tubes. First, a numerical model was constructed with a commercial explicit finite element code. It will be first proven that the numerical simulation can produce sufficiently accurate results in an economic manner. Subsequently, the crushing behavior of aluminum and steel tubes with a cutout was experimentally characterized and their energy absorption capacity was evaluated in terms of mean crushing force, peak crushing force and specific energy absorption (SEA). Tubes of various lengths with a cutout located at different locations, subject to both quasi-static and dynamic impact loadings were considered. For steel tubes, the numerical simulation investigated the influence of the strain rate effect and variation in strain hardening ratio of the material. Empirical equations describing the mean and peak crushing forces of aluminum and steel tubes with a cutout were developed using linear and nonlinear regression methods applied to the results obtained from the numerical and experimental studies.     

A scheme to randomly generate surface dust points for the 3D complex variable boundary element method (CVBEM)

A scheme to randomly generate dust points on the surface of a three-dimensional (3D) object is proposed. This scheme will potentially eliminate the bias of a density of points which are approximately equally spaced on the surface, as well as eliminate possible weighting requirements for areas of higher density. This method has the potential to reduce computational effort, as fewer points might be required to define the surface area. The global trial function vector can be assigned to these dust points and then entered into the complex variable boundary element method (CVBEM) commercial code. This scheme can be applied to each piece of a system that is comprised of a connected multiple geometry. A noticeable benefit of this approach is that the same problem can be studied several times, using a new random distribution of surface points each time. The smallest error can then be determined and that run selected. The Mathematica code used to generate the scheme is attached as an appendix.     

美国食品安全管理法规与举措

以美国国会研究服务部对第107届国会就食品安全方面的一份报告为基础,主要对美国的公共健康问题现状、美国食品安全的联邦规范框架组成、美国食品安全控制最新进展和国会对食品安全提出的新议题做了综述,对我国的食品安全控制和管理体系的建设发挥一点借鉴作用。     

Measurement of the Metal Surface Acidity/Electronegativity of Pt(110)

In previous work, it has been found that a hydrogen-covered Pt(110) surface is acidic, but quantification of the acidity has not yet been done. In this paper a spectroscopic method is developed to measure the acidity of a metal surface for the first time. The technique involves measuring the intensity of the N–H stretch from the C₅H₄XNH⁺ that forms when hydrogen coadsorbs with pyridine, 2-fluoropyridine and 3-fluoropyridine. The Bethe approximation is then used to estimate the metal surface acidity/electronegativity (MSAEL). The proton affinity/MSAEL of Pt(110) has been determined to be 907 ± 4 kJ/mol at high coverage. This is the first time the MSAEL has been measured on a metal surface. Implications for fuel cell catalysis are discussed.     

飞行时间二次离子质谱--强有力的表面、界面和薄膜分析手段

二次离子质谱（Secondary ion mass spectrometry，简称SIMS）是一种对表面灵敏的质谱技术，建立在表面各种类型带正、负电荷原子或分子发射的基础上。用飞行时间（Time of flight，简称TOF）仪器对这些二次离子进行质量分析，能确保并行质量登录、高质量范围、高流通率下的高分辨和精确质量测定这些优异性能。配合细聚焦扫描一次离子束，可在优于1nm的高深度分辨和优于50nm的横向分辨本领下，实现对表面优于单层ppm(百万分之一）量级的极高检测灵敏度。当今TOF－SIMS已发展为一种成熟且完善的表面分析技术。极高的灵敏度，再加上即使对大分子及不易挥发性分子都独具的敏感性，使它成为很多高技术领域不可缺少的分析手段，这些领域包括微电子学、化学和材料科学以至纳米技术和生命科学等。本文简述了TOF－SIMS的原理、仪器及其多方面的应用和展望。     

虚拟专用网的体系结构及实现

提出VPN接入设备的体系结构 ,包括系统的应用模型、层次划分和内部详细结构 ,阐述实现VPN的关键技术。     

Mechanical and microstructure studies on the modification of CA film by blending with PS

DriedMusa paradiciaca (banana) stem and veins of the leaves, which were hitherto discarded as a waste, were collected and used as starting material for the preparation of cellulose and cellulose acetate. This cellulose acetate was mixed with polystyrene to form blend of cellulose acetate-polystyrene in order to provide enhanced stability and extended utility to the end products. The films of these composites or their individual partners were made separately and studied for their mechanical properties, chemical modification and morphological changes. We report here that banana stem is good source of cellulose and that cellulose completely undergoes modification upon esterification.     

Strength of Metals at High Strain Rates

Results of metal testing in impact tension–compression and indentation are analyzed. As the analysis of these data demonstrates, the strength of metals increases greatly with strain rates and at moderate indentation rates. At high indentation rates, a decrease in the specific energy (per unit volume of a displaced material) necessary for the formation of a conical cavity was observed. The account of the effects of viscosity, temperature increase upon plastic deformation and its localization can be used to explain the above phenomena.     

新型微合金非调质钢的研究

研制了一种新型微合金非调质钢。通过合理设计合金成分,改善熔炼脱氧过程,控制钢中氧化物的组成、分布、形状和尺寸,在研制钢中形成微细的氧化物夹杂作为晶内铁素体最有利的析出位置。通过晶内铁素体的析出细化了晶粒,提高了钢的强度与韧性。将研制的新型微合金非调质钢用于拖拉机的牵引插销是可行且有效的。